1. Field of the Invention
This invention is related to the field of storage management and, more particularly, to software used in storage management.
2. Description of the Related Art
In the past, large organizations relied heavily on parallel SCSI technology to provide the performance required for their enterprise data storage needs. More recently, organizations are recognizing that the restrictions imposed by SCSI architecture are too costly for SCSI to continue as a viable solution. Such restrictions include the following:                SCSI disk arrays must be located no more than 25 meters from the host server;        The parallel SCSI bus is susceptible to data errors resulting from slight timing discrepancies or improper port termination; and        SCSI array servicing frequently requires downtime for every disk in the array.        
One solution has been to create technology that enables storage arrays to reside directly on the network, where disk accesses may be made directly rather than through the server's SCSI connection. This network-attached storage (NAS) model eliminates SCSI's restrictive cable distance, signal timing, and termination requirements. However, it adds a significant load to the network, which frequently is already starved for bandwidth. Gigabit Ethernet technology only alleviates this bottleneck for the short term, so a more elegant solution is desirable.
The storage area network (SAN) model places storage on its own dedicated network, removing data storage from both the server-to-disk SCSI bus and the main user network. This dedicated network most commonly uses Fibre Channel technology, a versatile, high-speed transport. The SAN includes one or more hosts that provide a point of interface with LAN users, as well as (in the case of large SANs) one or more fabric switches, SAN hubs and other devices to accommodate a large number of storage devices. The hardware (e.g. fabric switches, hubs, bridges, routers, cables, etc.) that connects workstations and servers to storage devices in a SAN is referred to as a “fabric.” The SAN fabric may enable server-to-storage device connectivity through Fibre Channel switching technology to a wide range of servers and storage devices.
The versatility of the SAN model enables organizations to perform tasks that were previously difficult to implement, such as LAN-free and server-free tape backup, storage leasing, and full-motion video services. SAN deployment promises numerous advantages, including cost management through storage consolidation, higher availability of data, better performance and seamless management of online and offline data. In addition, the LAN is relieved of the overhead of disk access and tape backup, data availability becomes less server-dependent, and downtime incurred by service and maintenance tasks affects more granular portions of the available storage system.
Many SAN management offerings in today's marketplace offer the ability to understand the physical connectivity of the SAN through the discovery of device interconnects. By providing a one-sided view of the SAN, these offerings display only a switches perspective of physical connections.
Many adopters of the SAN storage model face the problem that accompanies every new technology and design: a scarcity of professionals experienced with the technology. The job of SAN administrator is often filled by people with various skill sets and work backgrounds: mainframe operators, traditional network administrators, system administrators, and others in the IT industry. Some of the roles typically expected of a SAN administrator are securing the SAN and developing a data protection strategy, provisioning and administering SAN resources, testing new vendors' hardware and integrating the hardware into the SAN, troubleshooting SAN elements, and managing day-to-day performance and SAN resource availability. Where external SAN security is an issue, the SAN administrator may work in conjunction with network administrators and others in the IT department. Internal SAN security, however, is often solely the SAN administrator's responsibility.
Keeping track of devices and their connections in the SAN is a daunting task. Today, many administrators track and provision their SAN using spreadsheets and inventory reports that are typically immediately outdated.